How to Fix the “Sorry that site is reserved.” Message

That message is generated by WordPress when you try to create a site with the same name as an existing user. This can happen whether from a user that was created as part of a subsite that was previously created and then deleted, or even if the user was just added separately. (The user can be a member of any existing site, so be sure to verify through /wp-admin/network/users.php). The keyword here in that message is “reserved.” WordPress reserves site names for existing users because with certain settings it allows users to create blogs and it wants the blog name to match the user name.

NS Cloner uses the WordPress blog name validation to make sure that a new site that is generated the result of a cloning operation is a valid site name and won’t lead to other issues after it is cloned.

To remedy this situation you have three options:

delete the user with the same name

manually edit the DB to change that username and re-use the original for the site